Irradiance data in Tokyo is downloaded from Japn Meteorological Agency. The data is from 2012.1.1 to 2018.1.1.
head(data)
## Date Irradiance ## 1 2012-01-01 8.02 ## 2 2012-01-02 8.14 ## 3 2012-01-03 8.59 ## 4 2012-01-04 10.49 ## 5 2012-01-05 11.29 ## 6 2012-01-06 9.89